In a wireless communication system which utilizes cells to increase system capacity, a mobile device, also known as User Equipment (UE), in idle or sleep mode wakes up at regular time intervals, known as paging occasions. The paging occasions are used by the UE to monitor the paging channel (PCH) of the camping cell and to measure the quality of the camping and neighboring cells. Reselection is the process of transitioning from a source cell to a target cell in a cellular wireless communications system. During reselection to another cell, the UE reads the essential system information, for example, System Information Blocks (SIBs), on the Broadcast Channel (BCH) of the target cell. For example, SIBs contain groups of related system information sent by the wireless network to the various UEs for operational management.
The behavior of the UE for PCH monitoring while collecting system information is not specified in the applicable wireless standards. In one example, the UE has the option to either monitor the paging channel (e.g., PCH) at the same time as it reads the system information (e.g., SIBs) on a broadcast channel (e.g., BCH) or to postpone the monitoring of the paging channel until a particular time interval, (e.g., no more than 50 ms) after all essential system information are collected. In the latter case, the mobile-terminated (MT) call setup performance will be impacted in terms of call set-up time. Also, the user may not be reached if the page arrives during the skipped paging occasions. Simultaneous monitoring of the PCH on the source cell and BCH on the target cell may be implemented by the UE in the case of intra-frequency cell reselection. However, in the case of inter-frequency cell reselection, such simultaneous monitoring may not be possible since the source and the target cell are on different frequency carriers. Instead, the UE typically skips the PCH monitoring until all the essential system information is collected on the target cell. Although this behavior is standard-compliant, it can have negative impact on the mobile-terminated (MT) call setup time and user reachability. This performance degradation is due to the time-consuming system information collection, especially in case of long discontinuous reception (DRX) cycles and sub-optimal RF conditions or both. Mobile users that often cross inter-frequency cell boundaries will be particularly impacted. The present disclosure addresses the problem of PCH monitoring while collecting system information and reduces the time during which UE cannot receive pages during inter-frequency cell reselection.